Sulu was born on Earth in San Francisco in 2237. Starfleet headquarters is also in San Francisco and perhaps this is why Sulu chooses the career
When he graduates from the academy Sulu is posted to the USS Enterprise NCC 1701 as a physicist
In 2265 Sulu becomes a member of the bridge crew and takes the post of senior helm officer. He holds this position for the next 25 years and has a key role in a lot of the Enterprises missions that now have legendary stasis.
In the early 2280's Sulu is still helmsmen when the Enterprise is an academy training vessel under the command of Captain Spock.
In 2290 at the age of 53 Sulu is awarded the command of his own ship, the USS Excelsior NCC 2000. The very ship which in 2285 he was partly responsible for sabotaging.
The Excelsior is classed as a prototype, Deep Space exploration vessel and Sulu's first mission as Captain is to explore the Beta Quadrant and catalogue gaseous anomalies. A familiar face among his crew is Janice Rand. Rand is an old friend from the Enterprise. She was Captain Kirks Yeoman for a time. She is communications officer with a rank of Commander. Another of his crew is a young Ensign Tovuk. The same Tuvok who goes on to be Security Chief on the USS Voyager NCC 74656 over a century later.
In 2293 Sulu displays his loyalty to his old friends from the Enterprise when he falsifiers reports to Starfleet Command and enters Klingon Space in an attempt at rescuing Kirk and McCoy from Rura Penthe. After the Enterprise rescues them Sulu again ignores orders and reveals the location of the new peace conference. Although this defies his orders it does allow Kirk and crew to prevent the assassination of the Federation President.
Throughout his career Sulu also finds time for a family. He has a daughter called Damora, she is born in the early 2270's. Perhaps influence by her fathers career she elects to enter Starfleet and eventually becomes helm officer on another USS Enterprise. The USS Enterprise NCC 1701 B.
The Enterprise B is an Excelsior class vessel. The same class that her father is captain of.
In 2370 nearly a century after Sulu takes command of the Excelsior his portrait still hangs in Starfleet Headquarters. Showing that he had a long and distinguished career.